Process for photographic printing in colors



June 7 1927.

L. DUFAY PROCESS FOR PHOTOGRAPHIC PRINTING IN COLORS Filed Jan. 25 1924 L/wl l Patented June 7, 1927.

UNITED STATES LOUIS nnrnir, or vnasnrrrns, FRANCE.

PROCESS FOR PHOTOGRAPHIC PRINTING IN COLORS.

Application filed January 25, 1924. Serial No. 688,568.

This invention relates to a process ofpre paring photographic proofs 111' colors, on

the necessity of having recourse to the ordir' nary photographic.manipulations which necessitate the use of various chemical re agents. I f

. This process is essentially characterized in that oneor more photographic proofs printed with fat ink (hereinafter described),

for instance, on paper or other suitable support, are colored either by projection of a color powder, capable of being retained by the ink, or by direct introduction of the color in the latter; the perviouspapers-or supports adapted to receive the impression are then directly applied and in a moist condition, on the proof or proofs coated with coloring material. I I The proof or proofs will therefore becapable of being reproduced in several similar ,copies; the number of copies varying with the dyeing power of the coloring matters used.

In the'acco'mpanying drawing and by way ofexample: r h

Fig. 1 illustrates the image incolors it is desired to reproduce in several coples, the conventional hatchings indicating the color 80 of the various portions of the image; Figs. 2, 3 and 4 illustrate the colored prints of the photographic proofs of the image obtained by the tric'hrome method; these proofs have been taken through colored selecting screens, for instance,"so that the proof (Fi 2) may reproduce only the red portions 0 the original proof, the proof Fig. 3) the blue portions and the proof 4) the yellow portions."

, Figs. 5,6, 7 show the reproduction of the colors obtained byapplying the paper or the pervious support, previously molstened, successively on each of the proofs, Figs. 2, 3, 4.

The process, forming the subject-matter 45 of the invention, essentially consists in printing, with a suitable ink, a fat ink for instance, by any printing process, a photographic proof. f to the ink is added an a glutinative or sticky material (fatty varnish, gum or the' like), this ink will be able to retain anypulverulent material driven on the surface oflthe proof, before drying. If this pulverulent material is colored, the proof will therefore give, by contact, several reproductions, thef'number of which will vary'with the dyeing power of the coloring matter used as a powdering. For that pur- '1. pose, it isrsufficient to slightly moisten the paper or on all pervious supports, without,

pape'ror pervious support adapted to receive the p'f'intingand' to apply it, in a moist condition, directly on the proof coated with coloring matter.

' It'will be possible, as shown in the accoimpanying drawin in order to obtain polychromatic repro' uctions to successively apply the paper or pervious support on a ser es of proofs, obtained from the same image, but the portions of which are differently-colored. It will thus be possible by starting from prints of selected proofs of the same image, to obtain trichrome reproductions which will all be exactly identical.

As illustrated in the drawing, it will be supposed that it is desired, starting from a color subject (Fig. 1) composed of blue, red, yellow, green and violet, to obtain identical reproductions, on paper for instance.

Three negatives are taken from the subject or image by means of colored selectin screens, for instance; and there is obtaine for example:

1-A negative. containing the red shades and the red shades of the violet colors.

2A negative containing the blue shades and the blue shades of the green and violet colors (Fig. 3).

3--A negative containing the yellow shades of the green colors.

These negatives will give three proofs printed with fatty ink and which are powdered as follows:

Proof No. 1=with a red color,

Proof No. 2=with a blue color,

Proof No. 3=with a yellow color, which will give the representations of Figs. 2,3, 4.

The paper or ervious support, previously moistened, will t en be applied on the proof N0. 1 (Fig. 2) which will permit the reproduction of the red colors of'the subject. The impression received by the pervious support is shown in Fig. 5. 1

This support, after suitable registerin will be applied on the proof No. 2 (Fi 5 which will permit the reproduction o the violet and blue shades (blue and red). The impression received by the pervious support is shown in Fig. 6.

The same support will then be applied on the proof No. 3 (Fig. 4) which will permit the reproduction of the yellow and green shades (blue and yellow). The final printing of the support is shown in Fig. 6 and reproduces the colors of the original subject or image.

The same series of operations efiected on other papers or pervious supports will therefore give as many reproductions of the subject or image asthe dyeing power of the coloring matters used will allow.

Instead of powdering the proofs with a coloring powder as indicated, this operation can be-avoided by directly adding the coloring-matter to the ink which can be of any nature whatever and by incorporating it therewith by grinding.

Meth' lene blue, fuchsin, methyl violet, tartrazine, which are capable of a perfect 'porphyrization and which have a consider- 'able dyeing power, give excellent results for the application of the present process. They- "give combinations of colors-of a great vari *ety, agoodtrichrome synthesis and print "in'gs which can reach several hundreds of I copies.

'tained on the material What I claim as my invention and desire to secure by Letters Patent is:

A process for color rinting comprising the following steps, pro ucing a plurality of color-separation negatives from a colored original, making a similarnumber of printing plates from these color-separation negatives, printing said printing plates with a fatty ink on a single support, powdering the printed impression after each impression with a water-soluble dye, said dye corresponding in color to the color filter used in making the printing plate, moistening a oredimpression, pressing the material against the composite powdered impression whereby a transferred impression is -obreproducing the coloredoriginal. Y In testimony whereof I have signed my fname to this specification.

' LOUIS DUFAY.

sheet of material adapted to receive a col- 1 

